Systematic review of the effect of dynamic fixation systems compared with rigid fixation in the anterior cervical spine

Anterior cervical fixation is a procedure widely employed in medical practice, with different fixation systems in use. This study aimed to perform a systematic review of the literature comparing the use of rigid and dynamic cervical plates regarding the fusion rate and complications. A search was conducted in PubMed, Lilacs, and Cochrane databases and selecting comparative studies on the use of rigid and dynamic cervical plates. Prospective randomized studies were selected to describe the final results regarding the clinical and radiological outcomes; comparative observational studies were also cited. Complications of using the dynamic cervical plate were also evaluated. Seven comparative studies were included in the review. Five of these were prospective and randomized studies that did not report significant differences in the clinical outcome. One study reported a faster fusion rate when dynamic cervical plate was used, and another study showed a higher fusion rate when a dynamic cervical plate was applied on multiple levels. Four studies investigated the complications of using a dynamic plate and reported that changes in the cervical curvature angle and material failure were the most frequent complications. There were no clinical differences between the two types of cervical fixation systems. A difference in the fusion rates could not be found at any follow-up time or in any of the studies. There was a loss of lordotic correction in the dynamic systems and a higher rate of complications in patients with a loss of lordotic correction.